1 /* 2 * Copyright (C) 2015 Broadcom 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU General Public License version 2 as 6 * published by the Free Software Foundation. 7 */ 8 9 /** 10 * DOC: VC4 KMS 11 * 12 * This is the general code for implementing KMS mode setting that 13 * doesn't clearly associate with any of the other objects (plane, 14 * crtc, HDMI encoder). 15 */ 16 17 #include "drm_crtc.h" 18 #include "drm_atomic.h" 19 #include "drm_atomic_helper.h" 20 #include "drm_crtc_helper.h" 21 #include "drm_plane_helper.h" 22 #include "drm_fb_cma_helper.h" 23 #include "vc4_drv.h" 24 25 static void vc4_output_poll_changed(struct drm_device *dev) 26 { 27 struct vc4_dev *vc4 = to_vc4_dev(dev); 28 29 drm_fbdev_cma_hotplug_event(vc4->fbdev); 30 } 31 32 struct vc4_commit { 33 struct drm_device *dev; 34 struct drm_atomic_state *state; 35 struct vc4_seqno_cb cb; 36 }; 37 38 static void 39 vc4_atomic_complete_commit(struct vc4_commit *c) 40 { 41 struct drm_atomic_state *state = c->state; 42 struct drm_device *dev = state->dev; 43 struct vc4_dev *vc4 = to_vc4_dev(dev); 44 45 drm_atomic_helper_commit_modeset_disables(dev, state); 46 47 drm_atomic_helper_commit_planes(dev, state, 0); 48 49 drm_atomic_helper_commit_modeset_enables(dev, state); 50 51 /* Make sure that drm_atomic_helper_wait_for_vblanks() 52 * actually waits for vblank. If we're doing a full atomic 53 * modeset (as opposed to a vc4_update_plane() short circuit), 54 * then we need to wait for scanout to be done with our 55 * display lists before we free it and potentially reallocate 56 * and overwrite the dlist memory with a new modeset. 57 */ 58 state->legacy_cursor_update = false; 59 60 drm_atomic_helper_wait_for_vblanks(dev, state); 61 62 drm_atomic_helper_cleanup_planes(dev, state); 63 64 drm_atomic_state_put(state); 65 66 up(&vc4->async_modeset); 67 68 kfree(c); 69 } 70 71 static void 72 vc4_atomic_complete_commit_seqno_cb(struct vc4_seqno_cb *cb) 73 { 74 struct vc4_commit *c = container_of(cb, struct vc4_commit, cb); 75 76 vc4_atomic_complete_commit(c); 77 } 78 79 static struct vc4_commit *commit_init(struct drm_atomic_state *state) 80 { 81 struct vc4_commit *c = kzalloc(sizeof(*c), GFP_KERNEL); 82 83 if (!c) 84 return NULL; 85 c->dev = state->dev; 86 c->state = state; 87 88 return c; 89 } 90 91 /** 92 * vc4_atomic_commit - commit validated state object 93 * @dev: DRM device 94 * @state: the driver state object 95 * @nonblock: nonblocking commit 96 * 97 * This function commits a with drm_atomic_helper_check() pre-validated state 98 * object. This can still fail when e.g. the framebuffer reservation fails. For 99 * now this doesn't implement asynchronous commits. 100 * 101 * RETURNS 102 * Zero for success or -errno. 103 */ 104 static int vc4_atomic_commit(struct drm_device *dev, 105 struct drm_atomic_state *state, 106 bool nonblock) 107 { 108 struct vc4_dev *vc4 = to_vc4_dev(dev); 109 int ret; 110 int i; 111 uint64_t wait_seqno = 0; 112 struct vc4_commit *c; 113 struct drm_plane *plane; 114 struct drm_plane_state *new_state; 115 116 c = commit_init(state); 117 if (!c) 118 return -ENOMEM; 119 120 /* Make sure that any outstanding modesets have finished. */ 121 if (nonblock) { 122 struct drm_crtc *crtc; 123 struct drm_crtc_state *crtc_state; 124 unsigned long flags; 125 bool busy = false; 126 127 /* 128 * If there's an undispatched event to send then we're 129 * obviously still busy. If there isn't, then we can 130 * unconditionally wait for the semaphore because it 131 * shouldn't be contended (for long). 132 * 133 * This is to prevent a race where queuing a new flip 134 * from userspace immediately on receipt of an event 135 * beats our clean-up and returns EBUSY. 136 */ 137 spin_lock_irqsave(&dev->event_lock, flags); 138 for_each_crtc_in_state(state, crtc, crtc_state, i) 139 busy |= vc4_event_pending(crtc); 140 spin_unlock_irqrestore(&dev->event_lock, flags); 141 if (busy) { 142 kfree(c); 143 return -EBUSY; 144 } 145 } 146 ret = down_interruptible(&vc4->async_modeset); 147 if (ret) { 148 kfree(c); 149 return ret; 150 } 151 152 ret = drm_atomic_helper_prepare_planes(dev, state); 153 if (ret) { 154 kfree(c); 155 up(&vc4->async_modeset); 156 return ret; 157 } 158 159 for_each_plane_in_state(state, plane, new_state, i) { 160 if ((plane->state->fb != new_state->fb) && new_state->fb) { 161 struct drm_gem_cma_object *cma_bo = 162 drm_fb_cma_get_gem_obj(new_state->fb, 0); 163 struct vc4_bo *bo = to_vc4_bo(&cma_bo->base); 164 165 wait_seqno = max(bo->seqno, wait_seqno); 166 } 167 } 168 169 /* 170 * This is the point of no return - everything below never fails except 171 * when the hw goes bonghits. Which means we can commit the new state on 172 * the software side now. 173 */ 174 175 drm_atomic_helper_swap_state(state, true); 176 177 /* 178 * Everything below can be run asynchronously without the need to grab 179 * any modeset locks at all under one condition: It must be guaranteed 180 * that the asynchronous work has either been cancelled (if the driver 181 * supports it, which at least requires that the framebuffers get 182 * cleaned up with drm_atomic_helper_cleanup_planes()) or completed 183 * before the new state gets committed on the software side with 184 * drm_atomic_helper_swap_state(). 185 * 186 * This scheme allows new atomic state updates to be prepared and 187 * checked in parallel to the asynchronous completion of the previous 188 * update. Which is important since compositors need to figure out the 189 * composition of the next frame right after having submitted the 190 * current layout. 191 */ 192 193 drm_atomic_state_get(state); 194 if (nonblock) { 195 vc4_queue_seqno_cb(dev, &c->cb, wait_seqno, 196 vc4_atomic_complete_commit_seqno_cb); 197 } else { 198 vc4_wait_for_seqno(dev, wait_seqno, ~0ull, false); 199 vc4_atomic_complete_commit(c); 200 } 201 202 return 0; 203 } 204 205 static const struct drm_mode_config_funcs vc4_mode_funcs = { 206 .output_poll_changed = vc4_output_poll_changed, 207 .atomic_check = drm_atomic_helper_check, 208 .atomic_commit = vc4_atomic_commit, 209 .fb_create = drm_fb_cma_create, 210 }; 211 212 int vc4_kms_load(struct drm_device *dev) 213 { 214 struct vc4_dev *vc4 = to_vc4_dev(dev); 215 int ret; 216 217 sema_init(&vc4->async_modeset, 1); 218 219 ret = drm_vblank_init(dev, dev->mode_config.num_crtc); 220 if (ret < 0) { 221 dev_err(dev->dev, "failed to initialize vblank\n"); 222 return ret; 223 } 224 225 dev->mode_config.max_width = 2048; 226 dev->mode_config.max_height = 2048; 227 dev->mode_config.funcs = &vc4_mode_funcs; 228 dev->mode_config.preferred_depth = 24; 229 dev->mode_config.async_page_flip = true; 230 231 drm_mode_config_reset(dev); 232 233 vc4->fbdev = drm_fbdev_cma_init(dev, 32, 234 dev->mode_config.num_crtc, 235 dev->mode_config.num_connector); 236 if (IS_ERR(vc4->fbdev)) 237 vc4->fbdev = NULL; 238 239 drm_kms_helper_poll_init(dev); 240 241 return 0; 242 } 243